At last, when they had trudged all the way round the building and were almost back to their starting point, Ujurak spotted a flat sheet of wood propped against the wall.

‘Under there,’ he said, giving Kallik a shove. ‘Stay there until I come back.’

Kallik padded off, and Lusa followed her, giving Ujurak a friendly poke with her snout as she went past. ‘Don’t be long,’ she said.

‘I won’t,’ Ujurak promised.

Toklo went last, squashing himself into the small space beside his friends. ‘I’ve never done so much hiding in my whole life,’ he grumbled.

Once they were safely under cover, Ujurak looked up at the top of the building and the stars beyond. He strained upward, feeling the wind start to lift him. His flat-face pelts fell away as his body changed. His legs shrank, his feet cramping into hooked claws. His sight sharpened; he could make out every crack and rough place on the side of the building. Feathers sprouted from his pink flat-face skin, and as he swept his arms upward they became wings, gleaming white in the moonlight. With a deep-toned cry, Ujurak swooped upward in the shape of a snowy white owl.

The cold night air flowed through his feathers as he flew far above the BlackPaths and the flat-face structures, but even here it was tainted with the reek of oil from below.

The lights in the buildings were tiny specks in the darkness; even the flames on the top of the tower were smaller than Tiinchuu’s hearth fire. Firebeasts with their glaring eyes crawled like fireflies across the devastated land.

I have to find out what’s going on, Ujurak told himself, letting his owl-sight roam from the sea to the mountains. I have to know. Everything I can see is important.

The map the nurse had made for him with sheets and blankets unfolded beneath him, from the ocean to the mountains, with the black fungus of the Propkin oil field blighting the land between them.

Wherever he looked, he could see buildings and BlackPaths, the silver pipes threading their way across the land. And as he went on looking, something seemed to happen; movement seethed on the ground beneath, as if a bear had stirred an ants’ nest with his paw.

The towers and pipes and BlackPaths were crawling outward, swallowing up the land that until then had been free of them. They crept along the coast and into the hills, flowing like a tide over the forests and the dens of Arctic Village, far into the distance, covering everything until the Last Great Wilderness had vanished.